Simultaneous hydrodesulfurization of thiophene and benzothiophene over NiMoS catalysts supported on γ-Al2O3 composites containing ZSM-5

Alumina composites containing microporous ZSM-5 (Z-5) and mesoporous ZSM-5 (MZ-5), corresponding to x ZA and x MZA, were developed by incorporating Z-5 and MZ-5 into γ - Al 2 O 3 , respectively. The two series of NiMoS/ x MZA and NiMoS/ x ZA catalysts were prepared with these two composites as supports, respectively, and were used for the simultaneous hydrodesulfurization (HDS) of thiophene (T) and benzothiophene (BT). The results show that NiMoS/ x MZA series catalysts exhibit higher HDS activity than that of NiMoS/ x ZA and NiMoS/γ-Al 2 O 3 , and the HDS activity of NiMoS/ x MZA catalysts increases with the increase of MZ-5. The high HDS activity can be mainly attributed to the synergistic effects of the efficient diffusing pore channels, high dispersion of type II NiMoS phases, suitable acidity, and moderate Mo-support interaction. Moreover, the product distribution of HDS shows that the NiMoS/ x MZA catalysts possess the dominant direct desulfurization (DDS) selectivity and the selectivity increases with the increase of MZ-5 content due to more corner sites and suitable Brønsted (B) acid sites, whereas the NiMoS/ x ZA catalysts perform more excellent hydrogenation (HYD) selectivity, and the selectivity increases with the increase of Z-5 content because of the existence of more edge sites. Based on this, the possible reaction network for T and BT hydrodesulfurization over the catalysts are proposed.